The present invention relates to a numerical control device (hereinafter referred to as an "NC device") for use with a machine tool, for example, and more particularly to an NC device including a graphic display unit.
NC machining devices machine a workpiece by specifying the position of a tool with respect to the workpiece in the form of corresponding numerical information. The NC machining device can machine workpieces of complex configuration with ease and high accuracy at a high production rate.
FIG. 1 of the accompanying drawings schematically shows a general machine tool controlled by a conventional NC device, the machine tool being a lathe by way of illustrative example. A cylindrical workpiece 11 fixedly clamped by a chuck 10 rotatable about a Z-axis has one end supported by a tip 12a of a tailstock 12. A cutting tool 14 is secured to a turret or tool base 13. For cutting the workpiece 11, the turret 13 is moved in the direction of the arrow Z to cause the cutting tool 14 to cut the workpiece 11.
Where the NC device includes a graphic display unit, the shape of the workpiece 11, a cutting path of the tool 14, and a finished shape of the workpiece 11 are displayed on the display unit for checking and machining program for possible interference between the workpiece and the tool and monitoring the cutting condition. The machining program is checked by displaying the tool path as indicated by dotted lines as shown, for example, in FIG. 2 of the accompanying drawings. Whether the workpiece and the tool interfere with each other or not is checked by the determined values of functions which express the shape and position of holder mechanisms composed of the chuck and tailstock. However, since the holder mechanisms have not been displayed as graphic patterns, it has heretofore not been possible to visually check for any interference between the workpiece and the tool through graphic representation.